I would search the web for car painting - it's essentially the same thing. Some things I think would be different
1. Different primer - some work better for AL, some for steel, some for rusty metal, ect.
generally, remove paint with something like 400 grit, then work up to 1500 or 2000 or so, prime, sand, prime, sand, ..... paint in thin layers until finished, closs if necessary, wet sand, wax.
In my limited experience painting part of a vehicle, it's also better to wet sand everything as opposed to dry.